Endless flexible belt for a printing system

Abstract

An intermediate transfer member (ITM) for use in a printing system. The ITM includes an endless flexible belt formed of an elongate belt having a longitudinal axis. Attached to lateral edges of the endless flexible belt along the longitudinal axis are a first elongate strip and a second elongate strip, each of the elongate strips including lateral formations on outward facing lateral ends thereof which are distal to the lateral edges of the belt. At least one of the first and second elongate strips includes a first longitudinal portion having a first elasticity, and a second longitudinal portion having a second elasticity, such that the second elasticity is greater than the first elasticity. The first portion is attached to the lateral edges of the flexible belt and the second portion extends between the first portion and the lateral formations.

The invention claimed is: 
     
       1. An intermediate transfer member (ITM) for use in a printing system to transport ink images from an image forming station to an impression station for transfer of the ink image from the ITM onto a printing substrate, wherein the ITM comprises:
 an endless flexible belt having a uniform belt width, said endless flexible belt formed of an elongate belt having a longitudinal axis; 
 a first elongate strip and a second elongate strip, said first and second elongate strips attached to lateral edges of said belt along said longitudinal axis, said first and second elongate strips each including lateral formations on outward facing lateral ends thereof, said outward facing lateral ends being distal to said lateral edges of said belt, 
 wherein, during use, said belt is configured to be guided by a guiding system through at least the image forming station, said guiding system comprising guide channels configured to receive said lateral formations, 
 wherein at least one of said first and second elongate strips has a strip width and includes a first longitudinal portion extending along said longitudinal axis and having first portion width and a first elasticity, and a second longitudinal portion extending along said longitudinal axis and having a second portion width and a second elasticity, said first portion being attached to said lateral edges of said belt and said second portion extending between said first portion and said lateral formations, 
 wherein said second elasticity is greater than said first elasticity. 
 
     
     
       2. The ITM of  claim 1 , wherein said lateral formations are configured to engage said guide channels, so that said belt is placed under tension in a width-ways direction perpendicular to said longitudinal axis, and is constrained to follow a continuous path defined by said guide channels. 
     
     
       3. The ITM of  claim 1  wherein said second portion is elastic in a width-ways direction perpendicular to said longitudinal axis. 
     
     
       4. The ITM of  claim 1 , wherein said first longitudinal portion is non-elastic, and said second longitudinal portion is elastic. 
     
     
       5. The ITM of  claim 1 , wherein only said first elongate strip includes said first portion and said second portion, and wherein said second elongate strip is non-elastic. 
     
     
       6. The ITM of  claim 1 , wherein said first elongate strip and said second elongate strip each include a said first portion and a said second portion. 
     
     
       7. The ITM of  claim 1 , wherein an elasticity of said second portion of said first elongate strip is sufficient to maintain said belt taut when said lateral formations are guided through their respective guide channels. 
     
     
       8. The ITM of  claim 1 , wherein a ratio between said second portion width and said first portion width is in the range of 1:1 to 1:15. 
     
     
       9. The ITM of  claim 1 , wherein said strip width is in the range of 20 mm to 40 mm. 
     
     
       10. The ITM of  claim 1 , wherein said first elasticity is at least 10.0, at least 20.0, at least 30.0, at least 40.0, at least 50.0 N/mm, at least 75.0, at least 100.0, at least 125.0, at least 150.0, at least 175.0, or at least 200.0 N/mm. 
     
     
       11. The ITM of  claim 1 , wherein said first elasticity is at most 5% elongation, at most 4% elongation, at most 3% elongation, at most 2% elongation, at most 1% elongation, at most 0.5% elongation, at most 0.2% elongation, or at most 0.1% elongation. 
     
     
       12. The ITM of  claim 1 , wherein said second elasticity is in the range of 0.1 to 10.0 N/mm, 0.1 to 8.0 N/mm, 0.1 to 5.0 N/mm, 1.0 to 5.0 N/mm, 2.0 to 5.0 N/mm, or 3.0 to 5.0 N/mm. 
     
     
       13. The ITM of  claim 1 , wherein said second elasticity is at least 5% elongation, at least 8% elongation, at least 10% elongation, at least 20% elongation, at least 30% elongation, at least 40% elongation, or at least 50% elongation. 
     
     
       14. The ITM of  claim 1 , wherein a ratio between spring constant measurements of said second elasticity and said first elasticity, when measured in N/mm on a sample having a sample width of 22 mm and a sample length of 10 mm, is at least 1:4, at least 1:6, at least 1:10, at least 1:12, at least 1:20, at least 1:30, at least 1:40, at least 1:50, at least 1:60, at least 1:70, at least 1:80, at least 1:90, or at least 1:100. 
     
     
       15. A method of forming the ITM of  claim 1 , the method comprising: obtaining said elongate flexible belt;
 obtaining said first elongate strip including said first and second longitudinal portions; 
 obtaining said second elongate strip; and 
 attaching said first and second elongate strips to said lateral edges of said elongate flexible belt. 
 
     
     
       16. A printing system comprising:
 a. an intermediate transfer member (ITM) including:
 (i) an endless flexible belt having a uniform belt width, said endless flexible belt formed of an elongate belt having a longitudinal axis; 
 (ii) a first elongate strip and a second elongate strip, each attached to lateral edges of said belt along said longitudinal axis, said first and second elongate strips each including lateral formations on outward facing lateral ends thereof, said outward facing lateral ends being distal to said lateral edges of said belt,
 wherein at least one of said first and second elongate strips has a strip width and includes a first longitudinal portion having a first portion width and a first elasticity, and a second longitudinal portion having a second portion width and a second elasticity, said first portion being attached to said lateral edges of said belt and said second portion extending between said first portion and said lateral formations, 
 wherein said second elasticity is greater than said first elasticity; 
 
 
 b. an image forming station at which droplets of ink are applied to an outer surface of said ITM to form ink images thereon; 
 c. an impression station for transfer of the ink images from said ITM onto a printing substrate; and 
 d. a guiding system comprising guide channels configured to receive said lateral formations, said guiding system extending at least through said image forming station and configured, during use, to guide said ITM along said image forming station. 
 
     
     
       17. The printing system of  claim 16 , wherein said second portion is elastic in a width-ways direction perpendicular to said longitudinal axis. 
     
     
       18. The printing system of  claim 16 , wherein said first longitudinal portion is non-elastic and said second longitudinal portion is elastic. 
     
     
       19. The printing system of  16 , wherein only said first elongate strip includes said first portion and said second portion, and wherein said second elongate strip is non-elastic. 
     
     
       20. A method of forming a flexible belt, the method comprising:
 a. obtaining an elongate flexible belt having a uniform belt width and a longitudinal axis, said belt being suitable for use as an ITM in a printing system, said elongate flexible belt having first and second lateral edges; 
 b. obtaining a first elongate strip having a strip width and including:
 a first longitudinal portion extending along said longitudinal axis and having a first portion width and a first elasticity, said first longitudinal portion extending along said first elongate strip at a first lateral end thereof; 
 lateral formations on a second lateral end of said first elongate strip; and 
 a second longitudinal portion extending along said longitudinal axis and having a second portion width and a second elasticity, said second longitudinal portion extending longitudinally between said first portion and said lateral formations, 
 wherein said second elasticity is greater than said first elasticity; 
 
 c. obtaining a second elongate strip having first and second lateral ends, and including lateral formations on said second lateral end thereof; and 
 d. attaching said second lateral ends of said first and second elongate strips to said first and second lateral edges of said elongate flexible belt.